For example, in order to improve the band use efficiency or the communication path switching performance when a failure occurs, transparent interconnection of lots of links (TRILL) and shortest path bridging (SPB) have been devised newly as routing protocols. Each of TRILL and SPB may be used as a multi-way communication path and allows high speed switching when a failure occurs. Since, in TRILL or SPB, all network (NW) apparatus such as data relaying apparatus in the network incorporate the same protocol, in an urban area or at an important base, a communication path for the third way or the fourth way may be secured and communication having high reliability may be implemented.
On the other hand, at a deserted place, the main function may be required for a NW apparatus is a packet relaying function, and the switching function among three ways or four ways may not be required. However, in order to secure the coexistence of a NW at a deserted place with a NW in an urban area, also at the deserted place, NW apparatus that incorporate such a protocol as TRILL or SPB are installed. Therefore, the cost increases.
Thus, if the compatibility of a protocol may be secured between TRILL/SPB and Ethernet (registered trademark), a communication NW having high reliability may be implemented at a low cost. As a related art, there is Japanese National Publication of International Patent Application No. 2014-502126.